Re: [Xen-devel] [PATCH] xen/pvh: Fix segment selector ABI

[Jan Beulich <jbeulich@xxxxxxxx>]

On 10.02.2020 14:29, Andrew Cooper wrote:
> On 10/02/2020 13:22, Jan Beulich wrote:
>> On 08.02.2020 16:19, Andrew Cooper wrote:
>>> --- a/docs/misc/pvh.pandoc
>>> +++ b/docs/misc/pvh.pandoc
>>> @@ -23,7 +23,7 @@ following machine state:
>>>   * `cs`: must be a 32-bit read/execute code segment with a base of ‘0’
>>>     and a limit of ‘0xFFFFFFFF’. The selector value is unspecified.
>>>  
>>> - * `ds`, `es`: must be a 32-bit read/write data segment with a base of
>>> + * `ds`, `es`, `ss`: must be a 32-bit read/write data segment with a base 
>>> of
>>>     ‘0’ and a limit of ‘0xFFFFFFFF’. The selector values are all 
>>> unspecified.
>> Wouldn't this want accompanying with an adjustment to
>> xen/arch/x86/hvm/domain.c:check_segment(), which right now
>> isn't in line with either old or new version of this doc?
> 
> What do you thing is missing?  It too is written with the expectation of
> %es being set up, which I checked before sending this patch.

The function for example looks to permit zero segment attributes
for both DS and ES. It also looks to permit non-writable
attributes for both, and a non-readable CS.

Jan

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